Moneris: Test to ensure cvd support is not added.

Since we've run into this problem multiple times now, I thought it might be good to add a simple test to make sure that anyone who decides to implement cvd for moneris will be at aware that this will cause issues (unless of course Moneris has changed how the accounts work).

I also added a comment to make it more clear that the test should not just be removed during cvd implementation.

@jduff @odorcicd 
/cc @snookca